This invention relates generally to packaging of normally fragile and frangible pouches and more particularly, relates to a novel package product comprising a skin-packaged pouch of the retort or like type fabricated by conventional skin packaging techniques to realize unexpected, desired shipping advantages.
A "retort pouch" as used herein consists of layers of metal and plastic film combinations or metalized films or sheets which have been bonded together along marginal edges thereof by thermal sealing together of said marginal edges to seal a product therein. The metal/plastic combinations may comprise polyester film or polyethylene or polypropylene films laminated together into a sandwich with aluminum foil therebetween. Such a pouch containing a product, such as food, which requires processing can be so treated in a retort vessel while the product is encased in the pouch. Thus, a food product which requires cooking can be packaged in a retort pouch and cooked thereafter in the same manner as a similar food product packaged in the conventional tin can. Such pouches normally are fragile and easily ruptured.
The use of tin cans for packaging of processed foods can be considered universally accepted and commercialized in this country. Tin cans have considerably more bulk than pouches and withstand harsher handling conditions then a pouch. Such a tin can inherently has greater stacking strength than a pouch. Further, the seal afforded by a tin can is not easily ruptured by handling and stacking of the tin cans. These desirable features of tin can storage of processed foods, liquids, medicinal products or the like are not available from an ordinary retort pouch containing such a product.
For instance, the seal afforded by marginal thermal sealing of the films or sheets forming the pouch will not withstand the same pressures as will a tin can. A pouch has little, if any, stacking strength. The films or sheets are so flexible as to encourage cracking of the pouch during handling of the pouches and especially in case of shipping such pouches in shipping cartons. For instance, merely randomly bulk packaging of such retort pouches in a shipping container encourages occurrence of such adverse damage to such retort pouches as the shipping cartons are tossed about during transport. Consequently, tin cans have been more universally used for packaging of food products, semi-solids and liquids which otherwise might be adequately packaged in retort pouches where safe handling of retort packages can be assured during shipping thereof.
The obvious advantages derived from use of retort pouches include reduced cost of the pouch as compared to a tin can and reduced weight and bulk thereof for more economical shipment. There has been some recognized use of retort pouches for packaging of food liquids and medicinal products in foreign countries and in special instances where such products are supplied to military personnel. However, it is generally recognized that retort pouches have not been more universally commercialized in this country for packaging of liquids, semi-solids, food and medicinal products or the like which exhibit a so-called "wave action" inside of the pouch during handling thereof. Such "wave action" results in forces exerted from interior of the pouch against the marginally sealed edges of the pouch tending to separate said edges.
The recited disadvantages of using retort pouches for packaging of products exhibiting such "wave action" in the pouch are avoided by means of the herein invention which effectively immobilizes the retort pouch on a desirably rigid substrate by means of conventional skin-packaging techniques. The inventor herein is not aware of any prior art teaching the use of conventional skin packaging techniques for avoiding such heretofore recognized disadvantages of retort pouch packaging of such products and thereby enjoy the recognized advantages of retort pouch packaging as compared to tin can packaging of such products.
Although particularly notable advantages have been derived from application of the invention to skin packaging of retort pouches, such advantages may also be derived from such packaging of hot packs, asceptic packages and the like.
It has been known to employ shrink-packaging techniques for immobilizing rigid or contoured products on a tray. In shrink-packaging, the tray with products thereon usually is passed through a heat tunnel at which time a layer of thermoplastic film is softened to wrap around the tray and products. This process is different from the skin-packaging process which employs a vacuum draw to suck the softened film into tight engagement down on the products and substrate. Such tight engagement of the film over the skin-package product is not achieved using shrink packaging techniques. Blister packaging also is not suitable for anchoring a pouch on a flat substrate.